Expedient synthesis of 17α,21-dihydroxy-9β,11β-epoxy- 16αmethylpregna- 1,4-diene-3,20-dione 21-acetate from prednisolone utilising a novel Mattox rearrangement

摘要

A six step transformation of prednisolone to 17a,21-dihydroxy-9b,11b-epoxy- 16a-amethylpregna-1,4- diene-3,20-dione 21-acetate has been achieved in 13% unoptimised yield. Novel conditions for effecting a Mattox rearrangement and double dehydration of prednisolone were identified. Enhanced knowledge on the oxidation of silyl D19,20-enol ethers and structural factors that impact the success of the oxidation are also presented.